Wireless networks are increasingly employed to provide various communication functions including voice, video, packet data, messaging and the like. One conventional wireless local area network (WLAN) architecture is an infrastructure configuration, typically employing one or more access points that coordinate communications for a number of stations. In other configurations, two or more wireless devices may communicate directly with one another in an ad hoc network, such as in the role of a peer to peer client in a WiFi Direct™ (WiFi Direct) network managed by a group owner. Due to the wide availability, popularity and convenience of WLAN-based wireless communications, it may be desirable for a single device to simultaneously participate in multiple networks. For example, a client device may operate as a station in one or more infrastructure networks or may operate as a peer client in one or more WiFi Direct networks.
For both infrastructure and ad hoc WLANs, various management functions are typically necessary to coordinate operation among the participants, including time synchronization, implementation of power management strategies, advertisement of availability and the like. In particular, conventional operation of a WLAN commonly involves the periodic transmission of a beacon message by a device acting in a management role such as the access point or the group owner. In other types of ad hoc networks, the management functions may be shared among the participating devices. Accordingly, a client device participating in multiple networks may receive periodic beacons sent by the device acting in a management role for each network.
However, the networks typically will be independent of each other so that the beacons sent by the respective manager devices may be transmitted at arbitrary times with regard to each other. Generally, the client device may not be able to receive more than one transmission at a time, and therefore may not reliably receive beacons from all the networks as a result. For example, the management devices for two or more networks may send beacons at times that are sufficiently close to preclude the client device from receiving more than one of the beacons. When more than one of the networks have similar beacon intervals, this potential conflict may reoccur with each beacon transmission. Even if different networks employ different beacon intervals, collisions may still occur intermittently when the beacon transmission times align sufficiently.
A subset of the beacons may include delivery traffic indication map (DTIM) information that may be used to signal that multicast or broadcast traffic has been buffered and will be transmitted following the DTIM beacon. Accordingly, a client device upon receiving a DTIM beacon may remain in active mode in order to receive the buffered data. Receipt of the DTIM beacon may be relatively important for performance of the WLAN as the buffered data will be transmitted following the DTIM beacon, so if the client device is not in active mode, it will not receive the frames.
Without a strategy for selecting which beacon to receive, the beacon from one network may be chosen more frequently relative to others for an arbitrary reason, such as by being sent marginally earlier. Further, networks employing a longer interval may experience a relative degradation in performance as a greater proportion of beacons from networks using a shorter interval may be received.
Therefore, there is a need for a client device participating in multiple WLANs to selectively receive beacons from the networks to achieve a more desired reception rate. Further, there is a need to preferentially receive DTIM beacons. This invention satisfies these and other needs.